Skokanewbie

Hi there, hope someone might be able to shed some light on this. I have recently noticed to things which may or may not be related. On startup I can hear the heating/ventilation flaps move into position. What is most annoying happens at approx. 1,200 revs in Normal gear mode, a weird vibration noise can be heard from behind the central area of the dashboard, all fitting remains snug. If I use Sports gear mode the vibrations are more pronounced and happen at higher revs. The car runs perfectly but this is annoying given how silent it is on the road. Any help is gratefully appreciated. Gerry